ELENA BECATOROSATHENS, Greece (AP) â¿¿ Greeks head to the polls Sunday in their most critical â¿¿ and uncertain â¿¿ election in decades, with voters set to punish the two main parties that are being held responsible for the country's dire economic straits. Such is the disillusionment with the socialist PASOK party and conservative New Democracy, which have been alternating in power for the last 38 years, that neither is expected to garner enough votes to form a government. Days of wrangling over forming a coalition will likely ensue, with the prospect â¿¿ alarming to Greece's lenders and much of the country's population â¿¿ of another round of elections if they fail. Public anger has been so high that politicians have been forced to maintain low-profile campaigns for fear of physical attacks on the streets in a country battered by business closures and hundreds of thousands of job losses. The last opinion polls published before a two-week blackout ahead of the election showed PASOK and New Democracy hemorrhaging support since the last election in 2009. Their support has reached historic lows, plunging to percentages last seen in the mid-1970s after the 1974 fall of the seven-year military dictatorship. The stakes couldn't be higher. Entirely dependent on billions of euros worth of international rescue loans from other European countries and the International Monetary Fund, Greece must impose yet more austerity measures next month, if it is to keep the money flowing and prevent a default and a potentially disastrous exit from the euro. New Democracy leader Antonis Samaras is expected to come in first, thereby benefiting from a bonus 50 seats in the 300-member parliament. But even with that he would fall far short of the 151 seats needed to form a government. Opinion polls projected him winning not more than 25.5 percent.